[commit: bytestring] master: Include non-0 offset in instance Arbitrary Strict.ByteString (727e640)

[Ian Lynagh]

Repository : ssh://darcs.haskell.org//srv/darcs/packages/bytestring

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/727e6405ae5c83f7da40a1866c7b9c6a98441797

>---------------------------------------------------------------

commit 727e6405ae5c83f7da40a1866c7b9c6a98441797
Author: Duncan Coutts <duncan at community.haskell.org>
Date:   Mon Nov 7 11:30:08 2011 +0000

    Include non-0 offset in instance Arbitrary Strict.ByteString
    And fix a test that breaks.

>---------------------------------------------------------------

 Data/ByteString/Internal.hs |    2 +-
 tests/Properties.hs         |    4 +++-
 tests/QuickCheckUtils.hs    |    5 ++++-
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/Data/ByteString/Internal.hs b/Data/ByteString/Internal.hs
index bc91146..d9a3baf 100644
--- a/Data/ByteString/Internal.hs
+++ b/Data/ByteString/Internal.hs
@@ -317,7 +317,7 @@ unpackAppendCharsStrict (PS fp off len) xs =
 -- | The 0 pointer. Used to indicate the empty Bytestring.
 nullForeignPtr :: ForeignPtr Word8
 #ifdef __GLASGOW_HASKELL__
-nullForeignPtr = ForeignPtr nullAddr# undefined --TODO: should ForeignPtrContents be strict?
+nullForeignPtr = ForeignPtr nullAddr# (error "nullForeignPtr") --TODO: should ForeignPtrContents be strict?
 #else
 nullForeignPtr = unsafePerformIO $ newForeignPtr_ nullPtr
 {-# NOINLINE nullForeignPtr #-}
diff --git a/tests/Properties.hs b/tests/Properties.hs
index 0237ebf..d50e970 100644
--- a/tests/Properties.hs
+++ b/tests/Properties.hs
@@ -1537,7 +1537,9 @@ prop_packMallocCString (CByteString x) = unsafePerformIO $ do
          let !z = y == x
          free ptr `seq` return z
 
-prop_unsafeFinalize    x = unsafePerformIO $ do
+prop_unsafeFinalize    x =
+    P.length x > 0 ==>
+      unsafePerformIO $ do
         x <- P.unsafeFinalize x
         return (x == ())
 
diff --git a/tests/QuickCheckUtils.hs b/tests/QuickCheckUtils.hs
index 075dca6..4c61216 100644
--- a/tests/QuickCheckUtils.hs
+++ b/tests/QuickCheckUtils.hs
@@ -89,7 +89,10 @@ instance CoArbitrary L.ByteString where
   coarbitrary s = coarbitrary (L.unpack s)
 
 instance Arbitrary P.ByteString where
-  arbitrary = P.pack `fmap` arbitrary
+  arbitrary = do
+    bs <- P.pack `fmap` arbitrary
+    n  <- choose (0, 2)
+    return (P.drop n bs) -- to give us some with non-0 offset
 
 instance CoArbitrary P.ByteString where
   coarbitrary s = coarbitrary (P.unpack s)